Horrendous reviews and a terrorist-related plot didn't keep moviegoers from seeing Arnold Schwarzenegger's new action film Collateral Damage over the weekend. The pic — delayed four months due to Sept. 11 — opened at No. 1 with a so-so $15.2 million. Family pic Big Fat Liar, starring Malcolm in the Middle's Frankie Muniz, debuted at No. 2 with $11.7 million, followed by the critically thrashed remake of Rollerball (No. 3 with $9 million). And after four weeks on top, Black Hawk Down slipped to No. 4 with $8 million. Overall box office receipts were off 22 percent from this time last year. For an explanation, read on...